Difficulty of repairing all-electric injection molding machines is mainly reflected in repair technology of circuit boards. Following mainly talks about experience and skills of circuit board repair.
In fact, it is a software problem, such as system parameter loss, controller failure to start; such as position parameter loss, machine alarm position error, and even some garbled characters, etc. Most of these problems are caused by loss of data due to fact that backup battery has not been replaced for a long time.
To avoid above-mentioned faults, it is necessary to ensure that backup battery is replaced on time within time specified by each manufacturer.
To repair a relatively unfamiliar injection molding machine circuit board, it is difficult to work according to past experience without any schematic diagram. Even if you have been repairing hydraulic injection molding machines for many years and are quite confident in repair technology, you will feel powerless when repairing all-electric injection molding machines with experience of repairing hydraulic injection molding machines in the past.
So, how can you repair all-electric injection molding machines? According to long-term experience of injection molding machine repair center of Kaitai Injection Molding Machine, following steps should be followed and carried out in an orderly manner.

 

Take a look
When you hold a circuit board of an injection molding machine to be repaired, the first thing to do is to visually inspect it.
Mainly look at:
1. Is there a broken wire?
2. Is there a burning phenomenon, such as bulging resistors, electrolytic capacitors, inductors, diodes, triodes, and ICs with obvious burning marks?
3. Is there water or oil ingress? Most of circuit boards of all-electric injection molding machines are digital circuits, which are very sensitive to resistance. If water or oil ingress changes circuit resistance, logical errors will occur;
4. Has it been repaired or damaged? Are there any operational errors such as cold soldering, reverse insertion, copper foil disconnection, and leaking soldering?
5. Are there any components with high temperature? Pay special attention to power supply part, large power components, and ICs.
Compare
If you can find a good circuit board that is same as the one to be repaired as a reference, you can then use a multimeter, oscilloscope, and other tools to compare two boards. You can compare I/O voltage and resistance of circuit board. If you have an oscilloscope, you can also compare waveform frequency.
Experience: Due to harsh working environment of injection molding machine, failure rate of capacitors is relatively high (leakage, reduced capacity, etc.).
Replace
When problem is detected, or fault range has been narrowed to a certain area, but it is impossible to determine point, we can use substitution method to find faulty component.
1. When power supply is short-circuited and you don’t know which component it is, you can connect an external adjustable power supply and modulate voltage to 50% of normal power supply. Then look at which IC or component has a significantly higher temperature. Generally, it is problem of this component.
2. Some components on circuit board may not be found to be same, so you need to check relevant information to see if there is a replacement for this component. If not, you need to analyze working function of this component. For example, a three-state transceiver, since this component mostly works in parallel, bad one can be removed. Generally, circuit board can be used, but some functions will fail. But this way you can find problem point.
During online testing or comparison of devices, for all devices that have passed test (or are relatively normal), please directly confirm test results for recording; for those that have not passed test (or are relatively out of tolerance), you can test them again. If they still fail, you can also confirm test results first, continue testing until all devices on board are tested (or compared), then go back to deal with those devices that have not passed test (or are relatively out of tolerance).
For devices that have not passed functional online test, instrument also provides a less formal but more practical treatment method. Since instrument can apply power supply of injection molding machine circuit board to corresponding power supply and ground pins of device through test clip, if power supply pin of device is cut, device will be separated from power supply system of injection molding machine circuit board. At this time, device will be tested online. Since other devices on injection molding machine circuit board will no longer interfere, actual test effect is equivalent to "quasi-offline", and accuracy rate will be greatly improved.
3. Use ASA-VI curve scanning test to compare devices that are not yet covered by test library.
Since ASA-VI intelligent curve scanning technology can be applied to comparative test of any device, as long as test clamp can clamp device and there is a reference board, through comparative testing, device also has a strong fault detection capability.
This function makes up for deficiency that online functional test of device is subject to test library, and expands detection range of instrument for fault of injection molding machine circuit board. In reality, there are often situations where it is impossible to find a good board for reference, and circuit structure of board to be repaired itself has no symmetry.
In this case, ASA-VI curve scanning comparison test function does not work, and online functional test cannot complete test of every device on injection molding machine circuit board due to incomplete device test library. Injection molding machine circuit board still cannot be repaired. This is limitation of circuit online repair instrument, just like there is no medicine that can cure all diseases.